Voltage regulating system



Jan. 10,1933.

A. BOYAJIAN 1,893,760

VOLTAGE REGULATING SYSTEM Filed April 1' 7, 1931 2 Sheets-Sheet l Inventor: Aram Boya jian, by His Attorney Jan. '10, 1933. BQYAJlAN 1,893,760

VOLTAGE REGULATING SYSTEM Filed April 17, 1951 2 Sheets-Shee 2 Fig.2.

Inventor: ATam Bogajian, H His Attorney.

Patented Jan. 10, i933 UNITED STATES PATENT. orrlce ARA]! BOYAJ'IAN, OF PITTSFIELD, MASSACHUSETTS, ABSIGNOR TO GENERAL ELECTRIC COMPANY, .A CORPORATION OF NEW YORK VOLTAGE REGULATING SYSTEK Application filed April 17, 1981. Serial No. 580,880.

My invention relates to voltage regulating systems and more particularly to such systems of the type known in the art as feeder regulators in which the voltage of a feeder or a load circuit is maintained substantially constant irrespective of variations of the voltage of the supply circuit to which it is connected.

Heretofore there have been devised various arrangements, of which the tap changing transformer is a well known example for transferring the connections of a load circuit to an alternating current supplyv circuit from a point of one potential to a point of different potential in response to variations in the potential of the load circuit .due to a change in load or any of the other well known causes. prior art have required the use of moving parts and contacts which were subjected to considerable deterioration and wear, since they were required to make and break heavy currents. In addition, it has been impossible to attain the desired fineness of regulation without the provision of an inordinate number of taps of intermediate potential.

It is an object of my invention to provide an improved voltage regulating system in which the connections from a load circuit to an alternating current supply circuit may be transferred from a point of one potential to a point of another potential without the use of any moving parts or contacts inthe power circuit.

It is another object of my inventionto provide an improved voltage regulating system including a tap' changing transformer in which a load circuit maybe transferred from one tap to another by the use of electric valves.

It is a further object of my invention to provide an improved voltage regulating system including a tap changing transformer in which a load circuit may be transferred from one tap to another by electric valve means in response to variations in the voltage of the load circuit. A

It is a still further object of my invention to provide an improved voltage regulating syste in which the connections from the Most of the ara-ngements of the load circuit to an alternatin current supply circuit may be transferred 'rom a point of one potential to a point of another potential and in which any potential intermediate these tem including a tap changing transformer in which a load circuit may e transferred from one tap to another by electric valve means in response to variation in the volta e of the I load circuit and in which a load vo tage intermediate any two adjacent taps of the transformer may be obtained by proper control of the electric valve means.

In accordance with my invention the alternating current supply circuit is connected to a device for establishing a plurality of points of relatively fixed potential such, for example, as an autotransformer winding and the load circuit is connected to each of the several points of different potential. Included in the connection between the load circuit and each of the points of different potential are a pair of electric valves con nected reversely in parallel, that is, with the cathode of one connected to the anode of the other. The several electric valves are provided with control grids which are excited in accordance with variations of the potential of the load circuit in sucha manner that only the valves included in a single connection to the load circuit are conductive at any given instant. However, according to a modification of my invention, the load current is rapidly transferred between adjacent points of dlfierent potential and the relative duration of-the period during which current is flowing from one point or the other is controlled in response to the voltage of the load circuit to secure an average potential intermediate those of the two adjacent points in a manner somewhat analogous to the operation of the vibratory contact regulator.

For a better understanding of my invention, together with other and further objects thereof, reference is bad to the following description taken in connection with' the accompanying drawings and its scope will be pointed out in the appended claims. Fig. 1 of the accompanying drawings is a diagrammatic'representation of my invention as applied to an arrangement for connecting a I load circuit to any of a plurality of taps of a tap changing transformer in response "to variations inthe potential of the load circuit, Fig. 2 represents a modification of'my invention which is particularly suitable for obtaining any-desired potential intermediate the potentials of two, adjacent points in a supply circuit of different potential, while ment for receiving energy from an alternating current circuit 10 transforming, it into alternating current at a proper voltage and supplying it to an alternating current load circuit 11 which is illustrated as supplying power to a load device 12. This apparatus includes a transformer 13 having a primary winding connected to the circuit 10 and a secondary winding provided with taps 14, 15 and 16 connected to points of different electrical potential and each connected to the load circuit 11. The connection 14 includes a pair of electric valves 17'and 18 reversely connected in parallel, that is, connected in parallel with the anode of one valve connected to the cathode of the other and vice versa. Similarly, the connections between the taps 15 and 16 and the load circuit 11 include valves 19 and 20, 21 and 22, respectively. Electric valves 17 to 22, inclusive, are each provided with an anode, a cathode, and a control grid, and may be of any of the several types well known in the art, although I prefer to use vapor electric discharge valves in which the starting of the current in a valve is determined by'the potential upon its control grid, but in which the current flowing throu h the valve may be interrupted only'by re ucing its anode potential below the critical value. In order selectively to transfer the load current between the several pairs of electric valves, I have provided an arrangement for exciting the control grids-of all but one pair of the several electric valves with an alternating potential which is out of phase with the respective anode potentials thus rendering the valves non-conducting. This arrangement comprises a single phase primary winding 23 energized directlyacross the load circuit 11' and a polyphase secon'lary winding 24 relatively rotatable with resp ct to the primary winding 23. The control grids of the several pairs of electric valves are excited from difierentphases of the polyphase secondary winding 24 through grid transformers 25, 26, and 27, respectively. Each of the several grid transformers 25, 26, and 27 are provided with primary windings connected across the several phases of the secondary winding 24 and witha .pai-rof secondary windings-each connected to energize the con- -of the circuit 11. For example, I have illustrated a direct current pilot motor 28 connected to rotate the primary .winding 23 through a worm and worm gear arrangement -29. The motor. 28 is provided with a pair of reversing field windings 30 and 31 adapt-.

-ed-to be energized from a source of direct potential, shown as a battery 32, through a two-way switch 33 which, in turn, is controlled by a solenoid 34, the winding of which is connected directly across the load circuit 11.

In explaining the operation of the abovedescribed apparatus, it will be assumed that the voltage of the load circuit 11 is initially normal and that the windings 23 and 24 have the relative positions indicated in the figure. Under this condition, the polarity of the potentials applied to the grids of the electric valves 19 and 20 are in phase with theiranode potentials, while the grid potentials of the other electric valves are opposite in phase with respect to their anode potentials so that current is being supplied to the load circuit 11 from the secondary winding of transthe voltage of the load circuit llshould tend to rise, due to a decrease of current drawn by the load device 12 or for any other cause, solenoid 34, which is normally biased to maintain the switch 33 in neutral position, is actuated to operate the switch 33 to its upper contact. The field winding 30 is now energized to cause motor 28 to rotate the secondary winding 23 with-respect to the secondary winding 24 to reverse the polarity of the potential induced in the phase winding connected to the grid transformers 26 and 27 so that the grid potentials of electric valves 21 and 22 are now in phase with their respective anode potentials, while the grid potentials of the other valves are out of phase with theiranode potentials. Energy is delivered now from the transformer 13 to the load circuit 11 through the connection 16 which, it is seen, is at a lower potential. Obviously, upon a decrease in the voltage of the load circuit 11, a reverse operation takes place to transfer the loadcurrent from the connection of lower potlential to a connection of higher potentia In Fig. 2 I have illustrated a modification of my invention which is particularly suitable for obtaining any desiredpotential intermetrolled in response to variations in the potential of the load circuit to give the desired regulation. In this arrangement, the load circuit 11 is connected to the alternating current supply circuit 10 through an autotransformer provided with two secondary taps 71 and 72 in addition to the common connection between the two circuits. The connections between the load circuit 11 and the taps 71 and 72 include reactors 68 and 69 and electric valves 73 and 74 and 75 and 76 respectively, the connection of the valves being similar to that described in connection with Fig. 1. The valves 73-76 are preferably of the vapor electric. discharge type. The grids of the electric valves 73 to 76 inclusive are excited from the secondary windings 78 to 81, respectively, of a grid transformer 77, the primary winding of which is energized across one diagonal of a voltage responsive bridge, the other diagonal of which is connected directly across the load circuit 11. The voltage responsive bridge may be of any of the several types well known in the art such, for example, as that illustrated comprising two opposite arms 82 and 83 consisting of resistors having very small current resistance characteristics and opposite arms 84 and 85, consisting of ballast lamps, having very positive current resistance characteristics.

The type of regulation effected by the above-described apparatus is of the so-called dynamic type in which the voltage to be regulated is continually fluctuating within predetermined limits, the relative duration of the periods during which current is supplied at the higher voltage andthose during which it is supplied at the lower voltage determining the average voltage of the load circuit 11. Assume, for example, that energy is being supplied to the load circuit through the tap 72 and the valves 75 and 76, the valves 73 and 74 being non-conducting at this instant. Since the voltage of the tap 72 will be equal to or lower than the lower limits of the voltage regulation, it will be assumed that the potential supplied by. this tap is below the normal potential of the load circuit 11. Under this condition the voltage responsive bridge becomes unbalanced in such a direction as to reverse the polarity of the potential applied to the grid transformer 77 so that the grids of electric valves 75 and 76 are made negative, while those of the valves 73 and 74 are made positive with respect to their anodes. The valves 73 and 74 are now conductive, and the load current is transferred to the tap 71. The voltage of the load circuit now tends to riseabove its normal value and the voltage responsive bridge will become unbalanced in the opposite direction, after a time interval dependent upon its thermal characteristics, to again reverse the polarity of the potential applied to the grid transformer 77 and to transfer be used.

The rapidity with which current is transferred between the taps 71 and 72 will de-' pend upon the thermal characteristics of the ballast lamps 84 and 85 and this transfer may be made to take place at such a speed that there will be no appreciable variation or flicker in the potential of the load circuit 11.

In Fig. 3 is illustrated a portion of a power circuit which shows a modification of my invention which is particularly applicable to the control of the voltage of a load circuit by means of an auto transformer. In this arrangement, provide an auto transformer having a main potential winding 35 and a combined buck and boost series winding 36. Associated with this auto transformer is a bridge circuit including a pair of electric valves reversely connected in parallel in each arm of the bridge. These valves, which I have illustrated'in the drawing as the valves 41 to 48, inclusive, are each provided with an anode, a cathode, and a control grid, and are preferably of the vapor electric discharge type as in the arrangement shown in Fig. 1. The series buck and boost winding 36 of the auto transformer is connected across one diagonal ofthe valve bridge, the supply circuit 10 is connected to one eof the other vertices, while the load circuit 11 is connected to the remaining Vertex. The other side of the supply circuit 10 and the load circuit 11 are connected together at the lower terminal of the potential winding 35. The control grids of the several electric valves 41 to 48, inclusive, may be excited by an arrangement similar to that shown in Fig. 1 with the exception that only a two phase secondary winding 24 need be used, the grids of each of the valves of two opposite arms of the bridge being excited from one phase of the two phase winding, or, if desired, the grid control arran ement illustrated in Fig. 2 may hile the arrangement just described is particularly suitable' for use in my improved regulating circuits, it is to be understood that it is also of general application and may be used in any case in which it is desired to reverse the polarity of an alternating current circuit such as is represented by the winding 36. The operation of this arrangement will be clear in view of the the grid potentials of electric valves 41, 42,

and 46 in phase with their respective anode potentials, currentwill flow from the supply circuiti10 through electric valves 41 and-42, down through the series winding 36, and through electric valves 45 and 46 to the load circuit 11. With current flowing in this circuit, it will be assumedthat the main potential winding 35 will induce a potential in the Winding 36 which Will tend to buck that of the circuit 10. Obviously, when the electric valves 43, 44 and 47, 48 are conducting, the current will flow from the supply circuit 10 in the opposite direction through the Winding 36 to the load circuit 11 and the potential of the supply circuit 10 will be boosted. By slightly overlappin the phase windings ofthe secondary win ing 24 of Fig. 1, however, the electric valves 41 to 48 may be rendered conducting simultaneously during their respective positive half cycles of anode potential which will result in a neutral condition,that is, one in which there is neither buck nor boost. If the grid control arrangement illustrated in Fig. 2 is employed, any potential intermediate the buck and boost may be readily obtained.

In Fig. 4 is illustrated a modification of my invention in which separate bucking and boosting transformers are used. In this arrangement, I provide an auto transformer 50, for example, for boosting the voltage of the supply circuit 10, provided with a potential winding 51 and a series Winding 52.

The series Winding 52 is connected directly 63 conducting, the potential winding 51 of between the supply circuit 10 and the load circuit 11, while the potential winding 51 isconnected across. the supply circuit 10 through a pair of electric valves 62 and 63 reversely connected in parallel as in the previous arrangements. Similarly, an auto transformer 53 is provided for buckingthe potential of supply circuit 10, this transformer comprising a main potential winding 54 connected across the supply circuit 10 through. a pair of electric valves 60 and 61 and a series winding 55 connected directly between the supply circuit 10 and the load circuit '11. As in the arrangement shown in Fig. 3, a two phase secondary winding 24 will-be required for exciting the grids of the electric valves 60 to 63, inclusive, if the grid control of Fig. 1 be used, although it will be clear that the grid control illustrated in Fig. 2 may be used. if desired. With electric valves 60 and 61rendered conducting, the

bucking transformer 53 will be energized to buck the potential of the alternating current circuit 10, while with electric valves 62 and auto transformer 50 will be energized to boost the potential of the supply circuit 10. If all of the electric valves are made con ducting simultaneously during their respec tive positive half cycles of anode potential,

the bucking and boosting effect will be neutralized and the load circuit 11 will be energized at the same potential as the supply circuit 10. Intermediate values may be obtained by' using the grid control arrangement illustrated in Fig. 2.

While I have described what I at present consider the preferred embodiments of my invention,- it will be obvious to those skilled in the art that various changes and modifications may be made Without departing from my invention, and I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. In combination, an alternating current supply circuit, a transformer winding provided with a plurality of electrically spaced terminals, an alternating current load circuit connected to said supply circuit through said winding, and means including a pair of .electric valves reversely connected in parallel interposed in the connections to certain of said terminals for determining the potential of said load circuit. 1

2. In combination, an alternating current supply circuit, a transformer winding pro.- vided with a plurality of electrically spaced terminals, an alternating current load circuit connected to said supply circuit through said winding, means including a pair of electric valves reversely connected in parallel interposed in the connections to certain of said terminals for determining the potential of said load circuit, and means responsive to.

the potential of said load circuit for controlling the conductivity of said valve means.

3. In combination, an alternating current supply circuit, an alternating current load circuit, a transformer winding for determining therelative potentials of said circuits, a plurality of electric valves for controlling the connections of said transformer winding, each of said valves being provided with 4. In combinatlon, analternating current supply circuit provided with a plurality of points of different electrical potential, an alternating current load circuit, electric valve means interconnecting said supply circuit and said load circuit, and means for controlling said valve means to selectively energize 10 means for selectively rendering said valves conductive.

6. In combination,-an alternating current supply circuit, a transformer winding provided with a plurality of electrically spaced 15 terminals, an alternating current load circuit connected to said supply circuit through said winding, a pair of electric valves in the connections to each of two of said terminals, each of said pairs of valves being reversely con nected in parallel, and means for selectively transferring the load current between the pairs of valves.

7. In combination, a transformer winding provided with at least three electrically spaced terminals, an alternating current load clrcuit, connections from said load circuit to each of said terminals, an electric valve included in each of two adjacent connections, and means for selectively rendering 'said valves conductive.

8. In combination, a transformer winding provided with end terminals and a terminal of intermediate potential, an alternating current load circuit, connections from said load circuit to each of said-terminals, a pairof electric valves connected in each of the connections to said intermediate terminal and one'of said end terminals, each of said pairs of valves being reversely connected in parallel, and means for transferring the load current between the pairs of valves. '9. In combination, an alternatingcurrent supply circuit provided with a plurality of points of different electrical potential, an alternating current load circuit, electric valve meansinterconnecting said supply circuit and said load circuit, and means respons sive tothe load potential for controlling said valve means to' selectively energize said load circuit from any of the several points of different potentials;

. 10. In combination, a transformer windingprovided with at least three electrically spaced terminals, an alternating current load circuit, connections-from said load circult to each of said terminals, a pair of electric valves included in each of two adjacent connections, each pair of said valves being reversely connected ih parallel, and means responsive to the load potential-for selectively rendering one pair of valves conducting 11 In combination, a transformer winding provided with at least three electrically spaced terminals, a load circuit, connections from said load circuit to each of said terminals, a pair of electric valves included in each of two adjacent connections, each of said valves bein provided with an anode, a cathode, an a control grid andeach pair of said valves being reversely connected in parallel, a source of alternating potential in phase with that across said transformer winding for exciting the several control grids, and means responsive to the load potential for reversing the polarity of the grid potentials with respect to the anode potentials of all but one pair of said valves.

12. In combination, a transformer winding provided with at least three electrically spaced terminals, a load circuit, connections from said load circuit to each of said terminals, a pair of electric valves included in' each of two adjacent connections, each of said valves being provided with an anode, a

cathode, and a control grid and each pair of valves being reversely connected in parallel, means for exciting the several control grids comprising a single phase primary winding energized with a potential in phase with that across said transformer winding and apolyphase secondary winding relatively rotatable with respect to said primary windin means for energizin the grids of each pan of valves from a di erent phase of said secondary winding, and means responsive to the potential of said load circuit for controlling'the relative position of said primary and secondary windings.

13. In a system ofregulation, an alternating current supply circuit, a transformer winding provided with a plurality of elec trically spaced terminals, an alternating currect load circuit, a plurality of electric valve means interconnectlng said load circuit and said supply circuit through certain of the several transformer terminals, and means for selectively rendering said valve means conductive.

14. In a system of regulation, a tap changing transformer, an alternating current load circuit, an electric valve connected between said load circuit and each tap of said transformer, and means for selectively transferring the load current between the several valves.

15. In combination, an alternating current supply circuit, provided with a plurality of points of different electrical potential, an alternating current load circuit, electric valve means interconnecting said supply circuit and said load circuit, and means for controlling said valve means to energize said load circuit at any desired potential intermediate the potentials of two adjacent points of said supply circuit.

16. In combination, an alternating current circuit, a transformer winding provided with to said supply circuit through said winding,

electric valve means included in certain of the transformer connections, and means for controlling said valve means to energize said load circuit at any desired potential intermediate the potentials of two adjacent transformer terminals.

17. 'In a system of regulation, a tap-changing transformer, an alternating current load circuit, connections including a plurality of electric valves between said transformer and said load circuit, and means for controlling said valves to energize said load circuit at any desired potential intermediate the potentials of two adjacent transformer terminals.

18.'In combination, an alternating current supply circuit provided with a plurality of points of difi'erent electrical potential, an alternating current load circuit, connections between said load circuit and said points of different potential, certain of said connections including an electric valve, and means for energizing said load circuit at an average potential intermediate the potentials of ad jacent connections comprising means for rapidly transferring the load current between said connections.

19. In combination, an alternating curren supply circuit provided with at least three points of different electrical potential, an alternating current load circuit, connections between said load circuit and said points of diflerent potential, an electric valve included in each of two adjacent connections, and means for impressing on said load circuit a otential intermediate the potentials of adjacent points comprising means for-rapidly transferring the load current between adjacent connections.

20. In combination, an alternating current supply circuit provided with a plurality of points of different electrical potential, an alternating current load circuit connected to the several points of said supply circuit, a pair of electric valves reversely connected in parallel in the connections to two adjacent points, and means responsive to the potential of the load'circuit for rapidly transferring the load current between said pairs of valves to maintain the potential of said load circuit at any desired average potential intermediate the potentials of the two adjacent points.

21. In combination, an alternating current supply circuit provided with a plurality of points of different electrical potential, a load circuit connected to the several points of said supply circuit, a pair of electric valves reversely connected in parallel in the connections to two adjacent points, each of said valves being provided with an anode, a cathode, and a control grid. means for energizing the several grids so that only one pair of valves is conductive at any given instant, and

means responsive to the potential of the load 1 circuit for controlling said energizing means to intermittently and alternately render one pair of valves conductive and the other nonconductive.

22. In combination, an alternating current supply circuit, provided with a plurality of points of different electrical potential, a load circuit connected to the several points of said supply circuit, a pair of electric valves reversely connected in parallel in the connections to two adjacent points, each of said valves being provided with an anode, a cathode, and a control grid, a transformer winding connected between the grid and cathode of each of the several valves, a potential responsive bridge having one diagonal connected across said load circuit, and connections for energizing said transformer windings in accordance with the potential across the other diagonal of said bridge.

23. In combination, an alternating current supply circuit, a load circuit, atransformer provided with a plurality of windings, a plurality of paths each including an electric valve, interconnecting said load circuit and said supply circuit, certain of said paths including one of said windings connected in an bridge and said supply and load circuit being interconnected through the other diagonal, and means for selectively transferrin the load current between the several arms 0 vsaid valve bridge circuit.

25. In combination, an alternating current supply circuit, a load circuit, an auto transformer provided with a series winding and a shunt winding, a bridge circuit, each arm of which includes a pair of electric valves reversely connected in parallel, said series winding being connected across one diagonal of said bridge and said sup ly and load circuits being interconnected t rough other diagonal and means for selectively passing the load current through either opposite arms of the bridge or through the adjacent arms of thebridge.

26. The combination of an alternating current circuit, a booster transformer connected to said circuit and provided with series and exciting windings, a circuit including a plurality of electric valves for determining the relative polarity of said windin s, and means responsive to an electrical con ition of said circuit for controlling the. conductivity of said valves.

27 In combination, an alternating current supply circuit, a load circuit, means includin a bridge circuit interconnecting said loa circuit and said supply circuit, each arm of said bridge circuit including an electric valve, and means for selectively controlling said valves to reverse the. polarity of the connect-ion between said supply circuit and said load circuit through said bridge circuit.

28. In combination, analternating current supply circuit, a load circuit, means including a bridge circuit interconnecting said load circuit and said supply circuit, a pair of electric valves reversely connected in parallel in-. cluded in each of the arms of said bridge, and means for selectively rendering conductive the valves included in theopposite arms of said bridge to reverse the polarity of the conmotion between said supply circuit and said load circuit through said bridge circuit.

29. In combination, an alternating current supply circuit, a transformer winding provided With a plurality of electrically spaced terminals, an alternating currentload circuit connected to said supply circuit through said Winding, electric valve means interposed in the connections to certain of said terminals, and means for controlling the conduc- 'tivity of said valve means to selectively utilize predetermined portions of said transformer winding for determining the potential of said load circuit.

In witness whereof, I have hereunto set my hand.

ARAM BOYAJIAN. 

